org.junit

Class Assume

java.lang.Object

org.junit.Assume

public class Assume
extends Object

A set of methods useful for stating assumptions about the conditions in which a test is meaningful. A failed assumption does not mean the code is broken, but that the test provides no useful information. Assume basically means "don't run this test if these conditions don't apply". The default JUnit runner skips tests with failing assumptions. Custom runners may behave differently.

A good example of using assumptions is in Theories where they are needed to exclude certain datapoints that aren't suitable or allowed for a certain test case.

Failed assumptions are usually not logged, because there may be many tests that don't apply to certain configurations.

These methods can be used directly: Assume.assumeTrue(...), however, they read better if they are referenced through static import:

 import static org.junit.Assume.*;
    ...
    assumeTrue(...);
 

Since:

4.4

See Also:

Theories

Constructor Summary

Constructors

Constructor and Description
Assume()

Method Summary

Modifier and Type	Method and Description
static void	assumeFalse(boolean b) The inverse of assumeTrue(boolean).
static void	assumeFalse(String message, boolean b) The inverse of assumeTrue(String, boolean).
static void	assumeNoException(String message, Throwable e) Attempts to halt the test and ignore it if Throwable e is not null.
static void	assumeNoException(Throwable e) Use to assume that an operation completes normally.
static void	assumeNotNull(Object... objects) If called with one or more null elements in objects, the test will halt and be ignored.
static <T> void	assumeThat(String message, T actual, org.hamcrest.Matcher<T> matcher) Call to assume that actual satisfies the condition specified by matcher.
static <T> void	assumeThat(T actual, org.hamcrest.Matcher<T> matcher) Call to assume that actual satisfies the condition specified by matcher.
static void	assumeTrue(boolean b) If called with an expression evaluating to false, the test will halt and be ignored.
static void	assumeTrue(String message, boolean b) If called with an expression evaluating to false, the test will halt and be ignored.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Assume

public Assume()

Method Detail

assumeTrue

public static void assumeTrue(boolean b)

If called with an expression evaluating to false, the test will halt and be ignored.

assumeFalse

public static void assumeFalse(boolean b)

The inverse of assumeTrue(boolean).

assumeTrue

public static void assumeTrue(String message,
                              boolean b)

If called with an expression evaluating to false, the test will halt and be ignored.

Parameters:

b - If false, the method will attempt to stop the test and ignore it by throwing AssumptionViolatedException.

message - A message to pass to AssumptionViolatedException.

assumeFalse

public static void assumeFalse(String message,
                               boolean b)

The inverse of assumeTrue(String, boolean).

assumeNotNull

public static void assumeNotNull(Object... objects)

If called with one or more null elements in objects, the test will halt and be ignored.

assumeThat

public static <T> void assumeThat(T actual,
                                  org.hamcrest.Matcher<T> matcher)

Call to assume that actual satisfies the condition specified by matcher. If not, the test halts and is ignored. Example:

:
   assumeThat(1, is(1)); // passes
   foo(); // will execute
   assumeThat(0, is(1)); // assumption failure! test halts
   int x = 1 / 0; // will never execute
 

Type Parameters:

T - the static type accepted by the matcher (this can flag obvious compile-time problems such as assumeThat(1, is("a"))

Parameters:

actual - the computed value being compared

matcher - an expression, built of Matchers, specifying allowed values

See Also:

CoreMatchers, JUnitMatchers

assumeThat

public static <T> void assumeThat(String message,
                                  T actual,
                                  org.hamcrest.Matcher<T> matcher)

Call to assume that actual satisfies the condition specified by matcher. If not, the test halts and is ignored. Example:

:
   assumeThat("alwaysPasses", 1, is(1)); // passes
   foo(); // will execute
   assumeThat("alwaysFails", 0, is(1)); // assumption failure! test halts
   int x = 1 / 0; // will never execute
 

Type Parameters:

T - the static type accepted by the matcher (this can flag obvious compile-time problems such as assumeThat(1, is("a"))

Parameters:

actual - the computed value being compared

matcher - an expression, built of Matchers, specifying allowed values

See Also:

CoreMatchers, JUnitMatchers

assumeNoException

public static void assumeNoException(Throwable e)

Use to assume that an operation completes normally. If e is non-null, the test will halt and be ignored. For example:

 \@Test public void parseDataFile() {
   DataFile file;
   try {
     file = DataFile.open("sampledata.txt");
   } catch (IOException e) {
     // stop test and ignore if data can't be opened
     assumeNoException(e);
   }
   // ...
 }
 

Parameters:

e - if non-null, the offending exception

assumeNoException

public static void assumeNoException(String message,
                                     Throwable e)

Attempts to halt the test and ignore it if Throwable e is not null. Similar to assumeNoException(Throwable), but provides an additional message that can explain the details concerning the assumption.

Parameters:

e - if non-null, the offending exception

message - Additional message to pass to AssumptionViolatedException.

See Also:

assumeNoException(Throwable)